This invention relates to a luminaire adapted to be mounted at the top of a post and to project or to direct light below a horizontal plane. More particularly, this invention is directed to a luminaire having a new and improved refractor structure adapted for outdoor use.
The present invention is specifically directed to use in an outdoor environment where efficient illumination, durability and resistance to vandalism are important considerations. The invention also provides a new and improved luminaire which is aestheticly attractive and relatively easy to maintain.
A number of prior art luminaires have incorporated prismatic structures to facilitate the directing and distribution of light from the luminaire. U.S. Pat. Nos. 31,353; 31,149,747 and 3,344,268 all generally disclose the concept of employing a multiplicity of prisms in the form of vertical or horizontal rib structure to distribute or direct the light from a luminaire. U.S. Pat. No. 3,395,273, discloses a street lamp luminaire comprising a plurality of prisms for directing light below the horizontal plane of the luminaire. The present invention is directed to providing a series of prismatic structures at both the exterior and interior of a refracting portion of an element having a unique integrated structure adapted to accomplish a number of additional objectives as will be pointed out below.
The use of a polycarbonate material in a refracting element for a street light luminaire is disclosed in U.S. Pat. No. 3,661,685. The present invention is a new and improved luminaire which employs the properties of polycarbonates not only to provide a refracting element having efficient optical qualities, but also to provide a durable element adapted for use in an outdoor environment.